Protecting case

ABSTRACT

A protecting case is disclosed for the outer end of a cylinder lock which is mounted for instance in a door. The protecting case is attached to the cylinder housing of said lock by means of a yielding locking member which when the case is pushed in place, the member yields or is kept aside, but which when the case has reached its proper position is released and enters into an attachment recess so that it preferably undetachably locks the case to the cylinder housing. A radially yielding locking ring is preferred as the locking member.

United States Patent Inventors HenrikkiMalminen Joensuu; Kaarlo Henrik Solitanner, Helsinki, both of Finland Appl. No. 827,830 Filed May 26, 1969 Patented Dec. 28, 1971 Assignee 0y Wartsila AB Helsinki, Finland Priority May 25, 1968 Finland 1468/68 PROTECTING CASE 4 Claims, 1 Drawing Fig.

U.S. Cl 70/452, 70/451 Int. Cl E05b 15/02 Field of Search 70/452,

Primary Examiner Robert L. Wolfe Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A protecting case is disclosed for the outer end ofa cylinder lock which is mounted for instance in a door. The protecting case is attached to the cylinder housing of said lock by means ofa yielding locking member which when the case is pushed in place, the member yields or is kept aside, but which when the case has reached its proper position is released and enters into an attachment recess so that it preferably undetachably locks the case to the cylinder housing. A radially yielding locking ring is preferred as the locking member.

PROTECTING CASE The invention relates to a protecting-case arrangement for a cylinder lock, which arrangement comprises a protecting case enclosing the outer end of the cylinder housing of a cylinder lock.

For instance in a door lock the cylinder housing is recessed into the door so that only the outer end of the cylinder housing is visible at the outside of the door. Many efforts have been made to protect this outer end against attempts to break the lock and to this end different kinds of hardened protecting disks and other similar means have been used. A common problem has always been the attachment of the protecting disk or the corresponding member. The attachment has to be very strong and reliable but at the same time practical and nonexpensive.

The object of the invention is to provide a protecting-case arrangement for the cylinder housing of a cylinder lock in which arrangement the protecting case completely protects the outer end of the cylinder housing and in which the attachment and the form of the protecting case are so made that the case forms an effective bar against breaking attempts. The invention is characterized in that the protecting case is attached to the cylinder housing by means of a yielding locking member which when the case is pushed in place, the member yields or is kept aside, but which, when the case has reached its proper position, is released and enters into an attachment recess so that is preferably undetachably locks the case to the cylinder housing. The strongest attachment is obtained if the locking member is a locking ring, because in this case the cross section of the locking member is the largest in any possible breaking section. It is also advantageous that the locking member be arranged to lock the case rotatably to the cylinder housing because in this instance the locking member cannot be broken by means of rotating the protecting case. Consequently, a protecting case which is rotatably fitted can be removed only by means of loading it in an axial direction with such a substantial load that the case, the cylinder housing or the locking member breaks. However, in practice it is difficult to load the case in an axial direction with such a substantial load that the said breaking would occur.

In order to make it difficult to grab the protecting case with any tool the outer surface of the protecting case can be given a substantially conical form, at least at the portion which is on the outside of the door surface or the like. Also any other suitable form, for example a slightly spherical form can be used to obtain the same effect.

The protecting case should of course be made of hard material, for instance of hardened steel. Usually surfacehardening will be sufficient, because surface-hardening rather effectively prevents the breaking of the lock by means of sawing or boring.

in the following an embodiment of the invention will be more fully described with reference to the attached DRAW- lNG which shows an axial section of a protecting-case arrangement according to the invention.

in the DRAWING 1 indicates a protecting case, 2 a cylinder housing in which is supported a rotatable plug cylinder of a cylinder lock, 3 a door surface or the like and 4 the locking member of the protecting case 1, in this case a yielding or resilient locking ring.

The protecting case 1 is fitted in place before the lock is mounted in the door. It is then easy to keep the locking ring 4 pressed into the deep attachment groove 5 of the cylinder housing by means of a suitable tool so that the protecting case can be pushed in place. it is of course possible that the deep attachment groove is not made in the cylinder housing, but in the protecting case. in this case the attachment ring is of course to be pressed outwards when the protecting case is put in place. However, a deep attachment groove in the protecting case weakens the case considerably, and consequently it is favorable that the deeper groove is made in the cylinder housahen the protecting case has been mounted in place, the locking ring is resiliently biased outwardly in the shown embodiment and due to its own inner tension and/or guiding by the bottom of the attachment groove remains in such a position that approximately one-half of the locking ring is in the groove of the protecting case and one-half in the groove of the cylinder housing. The protecting case 1 may be partly recessed into the door 3 as shown in the FIGURE or its outer surface may be almost completely conical. This being so it is very difficult to grab the case and consequently its removal by force is difficult.

The shown joint between the protecting case and the cylinder housing is undetachable and hence it is difficult to detect the combination of the key even if the door in which the lock is fitted is open. This contributes to an improvement of the reliability of the lock.

The invention is not limited to the embodiment shown but modifications of the invention are feasible within the scope of the following claims.

What is claimed is:

l. A lock arrangement comprising a cylinder lock, a protective cover for said lock, attachment means for connecting said protective cover to said lock, and a carrier for the lock, said lock comprising a cylinder housing and a rotatable plug supported in said housing, said housing having an end portion provided with an opening allowing insertion of a key, said protective cover including an end plate axially adjacent said end portion and covering a substantial portion of said plug, said end plate being provided with an opening aligned with said first-mentioned opening for insertion of the key, said protective cover further including a cylindrical flange for enveloping said end portion of said housing, at least the surface of said protective cover facing outwards of said lock being hardened, said protective cover being rotatably attached to said lock, said attachment means being fully concealed and interposed between said cylindrical flange and said end portion of said housing, said lock and cover being fitted in said carrier, said carrier being provided with, in coaxial relation, a first cylindrical bore receiving said housing and a second cylindrical bore receiving both said end portion of said housing and said cylindrical flange of said protective cover such that the exposed surface of the end plate of the protective cover is approximately flush with the outer surface of the carrier.

2. The combination as claimed in claim 1 wherein said cylindrical flange axially contacts said carrier internally of said second bore.

3. The protective cover of claim 1 wherein said end plate includes a sloping portion extending into said cylindrical flange.

4. The protective cover of claim 1 wherein said sloping portion is conically tapered. 

1. A lock arrangement comprising a cylinder lock, a protective cover for said lock, attachment means for connecting said protective cover to said lock, and a carrier for the lock, said lock comprising a cylinder housing and a rotatable plug supported in said housing, said housing having an end portion provided with an opening allowing insertion of a key, said protective cover including an end plate axially adjacent said end portion and covering a substantial portion of said plug, said end plate being provided with an opening aligned with said first-mentioned opening for insertion of the key, said protective cover further including a cylindrical flange for enveloping said end portion of said housing, at least the surface of said protective cover facing outwards of said lock being hardened, said protective cover being rotatably attached to said lock, said attachment means being fully concealed and interposed between said cylindrical flange and said end portion of said housing, said lock and cover being fitted in said carrier, said carrier being provided with, in coaxial relation, a first cylindrical bore receiving said housing and a second cylindrical bore receiving both said end portion of said housing and said cylindrical flange of said protective cover such that the exposed surface of the end plate of the protective cover is approximately flush with the outer surface of the carrier.
 2. The combination as claimed in claim 1 wherein said cylindrical flange axially contacts said carrier internally of said second bore.
 3. The protective cover of claim 1 wherein said end plate includes a sloping portion extending into said cylinDrical flange.
 4. The protective cover of claim 1 wherein said sloping portion is conically tapered. 